SigProfilerExtractor

SigProfilerExtractor allows de novo extraction of mutational signatures from data generated in a matrix format. The tool identifies the number of operative mutational signatures, their activities in each sample, and the probability for each signature to cause a specific mutation type in a cancer sample. The tool makes use of SigProfilerMatrixGenerator and SigProfilerPlotting. Detailed documentation can be found at: https://osf.io/t6j7u/wiki/home/

Table of contents

• Installation
• Functions
  • importdata
  • sigProfilerExtractor
  • estimate_solution
  • decompose
  • PlotActivity.py
• Video Tutorials
• Citation
• Copyright
• Contact Information

Installation

To install the current version of this Github repo, git clone this repo or download the zip file. Unzip the contents of SigProfilerExtractor-master.zip or the zip file of a corresponding branch.

In the command line, please run the following:

$ cd SigProfilerExtractor-master
$ pip install .

For most recent stable pypi version of this tool, In the command line, please run the following:

$ pip install SigProfilerExtractor

Install your desired reference genome from the command line/terminal as follows (available reference genomes are: GRCh37, GRCh38, mm9, and mm10):

$ python
from SigProfilerMatrixGenerator import install as genInstall
genInstall.install('GRCh37')

This will install the human 37 assembly as a reference genome. You may install as many genomes as you wish.

Next, open a python interpreter and import the SigProfilerExtractor module. Please see the examples of the functions.

Functions

The list of available functions are:

• importdata
• sigProfilerExtractor
• estimate_solution
• decompose

And an additional script:

• plotActivity.py

importdata

Imports the path of example data.

importdata(datatype="matrix")

importdata Example

from SigProfilerExtractor import sigpro as sig
path_to_example_table = sig.importdata("matrix")
data = path_to_example_table 
# This "data" variable can be used as a parameter of the "project" argument of the sigProfilerExtractor function.

# To get help on the parameters and outputs of the "importdata" function, please use the following:
help(sig.importdata)

sigProfilerExtractor

Extracts mutational signatures from an array of samples.

sigProfilerExtractor(input_type, out_put, input_data, reference_genome="GRCh37", opportunity_genome = "GRCh37", context_type = "default", exome = False, 
                         minimum_signatures=1, maximum_signatures=10, nmf_replicates=100, resample = True, batch_size=1, cpu=-1, gpu=False, 
                         nmf_init="random", precision= "single", matrix_normalization= "gmm", seeds= "random", 
                         min_nmf_iterations= 10000, max_nmf_iterations=1000000, nmf_test_conv= 10000, nmf_tolerance= 1e-15, get_all_signature_matrices= False)

Category	Parameter	Variable Type	Parameter Description
Input Data
	input_type	String	The type of input: "vcf": used for vcf format inputs. "matrix": used for table format inputs using a tab separated file. "bedpe": used for bedpe files with each SV annotated with its type, size bin, and clustered/non-clustered status. Please check the required format at https://github.com/AlexandrovLab/SigProfilerMatrixGenerator#structural-variant-matrix-generation. "seg:TYPE": used for a multi-sample segmentation file for copy number analysis. Please check the required format at https://github.com/AlexandrovLab/SigProfilerMatrixGenerator#copy-number-matrix-generation. The accepted callers for TYPE are the following {"ASCAT", "ASCAT_NGS", "SEQUENZA", "ABSOLUTE", "BATTENBERG", "FACETS", "PURPLE", "TCGA"}. For example, when using segmentation file from BATTENBERG then set input_type to "seg:BATTENBERG".
	output	String	The name of the output folder. The output folder will be generated in the current working directory.
	input_data	String	Path to input folder for input_type: vcf bedpe Path to file for input_type: matrix seg:TYPE
	reference_genome	String	The name of the reference genome (default: "GRCh37"). This parameter is applicable only if the input_type is "vcf".
	opportunity_genome	String	The build or version of the reference genome for the reference signatures (default: "GRCh37"). When the input_type is "vcf", the opportunity_genome automatically matches the input reference genome value. Only the genomes available in COSMIC are supported (GRCh37, GRCh38, mm9, mm10, and rn6). If a different opportunity genome is selected, the default genome GRCh37 will be used.
	context_type	String	Mutation context name(s), separated by commas (,), that define the mutational contexts for signature extraction (default: "96,DINUC,ID"). In the default value, 96 represents the SBS96 context, DINUC represents the dinucleotide context, and ID represents the indel context.
	exome	Boolean	Defines if the exomes will be extracted (default: False).
NMF Replicates
	minimum_signatures	Positive Integer	The minimum number of signatures to be extracted (default: 1).
	maximum_signatures	Positive Integer	The maximum number of signatures to be extracted (default: 25).
	nmf_replicates	Positive Integer	The number of iteration to be performed to extract each number signature (default: 100).
	resample	Boolean	If True, add poisson noise to samples by resampling (default: True).
	seeds	String	Ensures reproducible NMF replicate resamples. Provide the path to the Seeds.txt file (found in the results folder from a previous analysis) to reproduce results (default: "random").
NMF Engines
	matrix_normalization	String	Method of normalizing the genome matrix before it is analyzed by NMF (default: "gmm"). Options are, "log2", "custom" or "none".
	nmf_init	String	The initialization algorithm for W and H matrix of NMF (default: "random"). Options are "random", "nndsvd", "nndsvda", "nndsvdar" and "nndsvd_min".
	precision	String	Values should be single or double (default: "single").
	min_nmf_iterations	Integer	Value defines the minimum number of iterations to be completed before NMF converges (default: 10000).
	max_nmf_iterations	Integer	Value defines the maximum number of iterations to be completed before NMF converges (default: 1000000).
	nmf_test_conv	Integer	Value defines the number number of iterations to done between checking next convergence (default: 10000).
	nmf_tolerance	Float	Value defines the tolerance to achieve to converge (default: 1e-15).
Execution
	cpu	Integer	The number of processors to be used to extract the signatures (default: all processors).
	gpu	Boolean	Defines if the GPU resource will used if available (default: False). If True, the GPU resources will be used in the computation. Note: All available CPU processors are used by default, which may cause a memory error. This error can be resolved by reducing the number of CPU processes through the cpu parameter.
	batch_size	Integer	Will be effective only if the GPU is used. Defines the number of NMF replicates to be performed by each CPU during the parallel processing (default: 1). Note: For batch_size values greater than 1, each NMF replicate will update until max_nmf_iterations is reached.
Solution Estimation Thresholds
	stability	Float	The cutoff thresh-hold of the average stability (default: 0.8). Solutions with average stabilities below this thresh-hold will not be considered.
	min_stability	Float	The cutoff thresh-hold of the minimum stability (default: 0.2). Solutions with minimum stabilities below this thresh-hold will not be considered.
	combined_stability	Float	The cutoff thresh-hold of the combined stability (sum of average and minimum stability) (default: 1.0). Solutions with combined stabilities below this thresh-hold will not be considered.
	allow_stability_drop	Boolean	Defines if solutions with a drop in stability with respect to the highest stable number of signatures will be considered (default: False).
Decomposition
	cosmic_version	Float	Defines the version of the COSMIC reference signatures (default: 3.4). Takes a positive float among 1, 2, 3, 3.1, 3.2, 3.3, and 3.4.
	make_decomposition_plots	Boolean	Generate de novo to COSMIC signature decomposition plots as part of the results (default: True). Set to False to skip generating these plots.
	collapse_to_SBS96	Boolean	If True, SBS288 and SBS1536 de novo signatures will be mapped to SBS96 reference signatures (default: True). If False, those will be mapped to reference signatures of the same context.
Others
	get_all_signature_matrices	Boolean	Write to output Ws and Hs from all the NMF iterations (default: False)
	export_probabilities	Boolean	Create the probability matrix (default: True).
	volume	String	Path to the volume for writing and loading reference genomes, plotting templates, and COSMIC signature plots (default: None). Environmental variables take precedence: SIGPROFILERMATRIXGENERATOR_VOLUME, SIGPROFILERPLOTTING_VOLUME, and SIGPROFILERASSIGNMENT_VOLUME.

sigProfilerExtractor Example

VCF Files as Input

from SigProfilerExtractor import sigpro as sig
def main_function():
    # to get input from vcf files
    path_to_example_folder_containing_vcf_files = sig.importdata("vcf")
    # you can put the path to your folder containing the vcf samples
    data = path_to_example_folder_containing_vcf_files
    sig.sigProfilerExtractor("vcf", "example_output", data, minimum_signatures=1, maximum_signatures=3)
if __name__=="__main__":
   main_function()
# Wait until the excecution is finished. The process may a couple of hours based on the size of the data.
# Check the current working directory for the "example_output" folder.

Matrix File as Input

from SigProfilerExtractor import sigpro as sig
def main_function():    
   # to get input from table format (mutation catalog matrix)
   path_to_example_table = sig.importdata("matrix")
   data = path_to_example_table # you can put the path to your tab delimited file containing the mutational catalog matrix/table
   sig.sigProfilerExtractor("matrix", "example_output", data, opportunity_genome="GRCh38", minimum_signatures=1, maximum_signatures=3)
if __name__=="__main__":
   main_function()

sigProfilerExtractor Output

To learn about the output, please visit https://osf.io/t6j7u/wiki/home/

Estimation of the Optimum Solution

Estimate the optimum solution (rank) among different number of solutions (ranks).

estimate_solution(base_csvfile="All_solutions_stat.csv", 
          All_solution="All_Solutions", 
          genomes="Samples.txt", 
          output="results", 
          title="Selection_Plot",
          stability=0.8, 
          min_stability=0.2, 
          combined_stability=1.0,
          allow_stability_drop=False,
          exome=False)

Parameter	Variable Type	Parameter Description
base_csvfile	String	Default is "All_solutions_stat.csv". Path to a CSV file that contains the statistics of all solutions.
All_solution	String	Default is "All_Solutions". Path to a folder that contains the results of all solutions.
genomes	String	Default is "Samples.txt". Path to a tab delimilted file that contains the mutation counts for all genomes given to different mutation types.
output	String	Default is "results". Path to the output folder.
title	String	Default is "Selection_Plot". This sets the title of the selection_plot.pdf
stability	Float	Default is 0.8. The cutoff thresh-hold of the average stability. Solutions with average stabilities below this thresh-hold will not be considered.
min_stability	Float	Default is 0.2. The cutoff thresh-hold of the minimum stability. Solutions with minimum stabilities below this thresh-hold will not be considered.
combined_stability	Float	Default is 1.0. The cutoff thresh-hold of the combined stability (sum of average and minimum stability). Solutions with combined stabilities below this thresh-hold will not be considered.
allow_stability_drop	Boolean	Default is False. Defines if solutions with a drop in stability with respect to the highest stable number of signatures will be considered.
exome	Boolean	Default is False. Defines if exomes samples are used.

Estimation of the Optimum Solution Example

from SigProfilerExtractor import estimate_best_solution as ebs
ebs.estimate_solution(base_csvfile="All_solutions_stat.csv", 
          All_solution="All_Solutions", 
          genomes="Samples.txt", 
          output="results", 
          title="Selection_Plot",
          stability=0.8, 
          min_stability=0.2, 
          combined_stability=1.0,
          allow_stability_drop=False,
          exome=False)

Estimation of the Optimum Solution Output

The files below will be generated in the output folder:

File Name	Description
All_solutions_stat.csv	A csv file that contains the statistics of all solutions.
selection_plot.pdf	A plot that depict the Stability and Mean Sample Cosine Distance for different solutions.

Decompose

For decomposition of de novo signatures please use SigProfilerAssignment

Activity Stacked Bar Plot

Generates a stacked bar plot showing activities in individuals

plotActivity(activity_file, output_file = "Activity_in_samples.pdf", bin_size = 50, log = False)

Parameter	Variable Type	Parameter Description
activity_file	String	The standard output activity file showing the number of, or percentage of mutations attributed to each sample. The row names should be samples while the column names should be signatures.
output_file	String	The path and full name of the output pdf file, including ".pdf"
bin_size	Integer	Number of samples plotted per page, recommended: 50

Activity Stacked Bar Plot Example

$ python plotActivity.py 50 sig_attribution_sample.txt test_out.pdf

Video Tutorials

Take a look at our video tutorials for step-by-step instructions on how to install and run SigProfilerExtractor on Amazon Web Services.

Tutorial #1: Installing SigProfilerExtractor on Amazon Web Services

Tutorial #2: Running the Quick Start Example Program

Tutorial #3: Reviewing the output from SigProfilerExtractor

GPU support

If CUDA out of memory exceptions occur, it will be necessary to reduce the number of CPU processes used (the cpu parameter).

For more information, help, and examples, please visit: https://osf.io/t6j7u/wiki/home/

Citation

Islam SMA, Díaz-Gay M, Wu Y, Barnes M, Vangara R, Bergstrom EN, He Y, Vella M, Wang J, Teague JW, Clapham P, Moody S, Senkin S, Li YR, Riva L, Zhang T, Gruber AJ, Steele CD, Otlu B, Khandekar A, Abbasi A, Humphreys L, Syulyukina N, Brady SW, Alexandrov BS, Pillay N, Zhang J, Adams DJ, Martincorena I, Wedge DC, Landi MT, Brennan P, Stratton MR, Rozen SG, and Alexandrov LB (2022) Uncovering novel mutational signatures by de novo extraction with SigProfilerExtractor. Cell Genomics. doi: 10.1016/j.xgen.2022.100179.

Copyright

This software and its documentation are copyright 2018 as a part of the sigProfiler project. The SigProfilerExtractor framework is free software and is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

Contact Information

Please address any queries or bug reports to Mark Barnes at [email protected]